This invention relates generally to imaging, and more particularly, to detecting aneurysm in vasculature, especially in the brain, using a shape based method.
Aneurysms are a fundamental cause of hemorrhagic stroke and account for about twenty percent of all stroke cases. In an aneurysm, a portion of the brain ruptures and is filled with blood that can cause tissue death or pressure in the head. Large hemorrhages can be fatal and can be caused by large aneurysms that are typically clearly visible on a medical image. However, of particular interest and concern is the debilitating “dementia” like conditions caused by micro hemorrhages that are due to small aneurysm ruptures.
Aneurysms are infrequently encountered on a straight, non-branching segment of an intracranial artery. However, the aneurysms occurring on straight, non-branching segments are more often found to have sacs that point longitudinally along the wall of the artery in the direction of blood flow and to project only minimally above the adventitial surface. Aneurysms having these characteristics are of a dissecting type rather than of the congenital saccular type. The development of these aneurysms is caused more frequently by the onset of ischemic neurological deficits than by the subarachnoid hemorrhage associated with congenital saccular aneurysms.
The problem of detecting small aneurysms is particularly difficult for computed tomography angiography (CTA) exams as these aneurysms are very minute and are often indistinguishable from the vasculature. Additionally, the presence of bone in the skull causes added difficulty to visualize these structures. Thus, these aneurysms in the vascular network may not be detected by a typical CTA exam.
Known visualization methods provide complementary shape information that can aid in diagnosis of anatomical and/or clinical conditions. However, these template based methods provide information that can tend to overwhelm the user with either fragmented or at times false clinical information. Thus, even when this information is accurate, it is not presented to the user in a clinically efficient manner. The problem with inaccurate information is further compounded in CTA exams where the presence of bones can introduce filtering artifacts due to the shape similarities with objects of interest. This can lead to improper or incorrect diagnosis.